At present, subscribers usually receive telephony and cable TV services from different suppliers over separate networks. Power requirements for the networks are quite different. For example, in telephony networks, backup batteries must be supplied to continue services in the event of a power blackout. In cable TV systems, backup power is not required since a commercial power failure in the network usually means a power failure to the subscriber who would, therefore, not be able to receive the service anyway.
In the future, both types of services, as well as new broadband services (e.g., switched digital video), will be supplied from a single network. Such networks would still require backup power to maintain telephony service during commercial power outages. However, the presence of active RF components for providing broadcast TV in the network would create a substantial additional load on the batteries. If the active RF components could be powered down during commercial power outages, the size and number of batteries Could be reduced and the number of hours the batteries could operate would be increased.